In a known manner, a piece made of composite material comprises a fiber structure that is embedded in a hardened matrix.
This invention relates more particularly to a fiber structure that is obtained by the assembly of several fiber elements.
The document EP-556089 describes a process whose purpose is to make two fiber elements integral, a first fiber element being applied by one of its edges against a first surface of a second fiber element. According to this document, to ensure the connection, transverse fibers that pass through said second element from the second surface of said second element are introduced by tapping a continuous thread. The thread loops that are obtained by tapping have a suitable length for penetrating the first element enough to ensure the connection. The document FR-2,687,173 describes another technique for assembly of at least two fiber elements: namely a first element in the form of a panel and at least one second element in the form of an angle bar, of which one wing rests against a first surface of the panel. According to this document for ensuring the connection, transverse fibers that pass through the first element from the second surface of said element are introduced by tapping a continuous thread. The thread loops that are obtained by tapping have a suitable length for adequately penetrating the second element. According to the variants, the transverse fibers that are provided outside of the zone that corresponds to the wing of the angle bar that is perpendicular to the panel can protrude on both sides of the structure, on the one hand at one of the surfaces of the panel and on the other hand at the surface of the angle bar that is parallel to the panel. According to another variant, the loops can be inclined and are not perpendicular to the surface of the panel.
Regardless of the variant, the ends of the loops that are arranged at the wing of the angle bar perpendicular to the panel are embedded in the structure and do not protrude.
The techniques of the prior art do not make it possible to ensure sufficient resistance depending on various mechanical stresses.
Actually, the pieces made of composite material that contain structures that are obtained according to the prior art have limited mechanical characteristics in terms of flexion because the junction zone is low in fibers and rich in resin and in terms of shearing because of the poor properties of carbon fibers in shearing.
In addition, the pieces made of composite material are subject to delamination at the junction zone.